Human evolution; our complex speech mechanism (Introduction)

"Linguists told themselves many stories about the evolution of language, and so did evolutionary biologists; but stories, as Richard Lewontin rightly notes, are not hypotheses, a term that should be “reserved for assertions that can be tested.”

"The human language faculty is a species-specific property, with no known group differences and little variation. There are no significant analogues or homologues to the human language faculty in other species.5 The notion of a species-specific biological trait is itself unremarkable. Species-specific traits are essential to the very definition of a species, at least for multicellular animals requiring reproductive isolation,

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"Every human language is a finite computational system generating an infinite array of hierarchically structured expressions. This is the basic property (BP) of language. Every structured expression has a definite semantic interpretation and can be expressed by some sensory modality—speech when possible, gesture when not. The BP is best explained, we argued, as the expression of an underlying computational system, an example of those innate repertoires to which Tinbergen, Lorenz, and Lenneberg called attention.

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"Citing comparative avian work by Andreas Pfenning et al., we demonstrated that many of the systems for vocal learning and production must have been in place before the emergence of language.17 This follows the typical evolutionary pattern. By the same token, Elizabeth Atkinson et al. carefully reexamined FOXP2 together with the intronic regions that might have been involved in a selective sweep.18 They found that human-specific DNA and amino acid variations matched those of Neanderthals or Denisovans but not other non-human primates.

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"How far back does language go? There is no evidence of significant symbolic activity before the appearance of anatomically modern humans 200 thousand years ago (kya).22 The South African Blombos cave site contains abstract patterns using ochre crayon on silcrete. These have been dated to approximately 80 kya.23 There is no doubt that these patterns, which represent the earliest known drawings, were executed by anatomically modern humans. In 2018, Dirk Hoffman et al. claimed to have found cave art in Spain dating to roughly 65 kya and thus predating the earliest known arrival of modern humans in Europe.24 Dates have been corrected to approximately 47 kya, the time at which human beings appeared in Europe.

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"The emergence of language occurred earlier than we thought, and certainly earlier than we suggested.....Riny Huybregts ... concludes that the language faculty emerged with Homo sapiens, or shortly thereafter, but externalization in one form or another must have been a later development, and quite possibly involved little or no evolutionary change.

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"For all that, the chasm between phenotype, algorithm, and neural implementation remains just that—a chasm. We do not yet understand the space of algorithms that might inform, or guide, the BP.

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"There is a common, conserved genetic toolkit for building vocal learners, one aligned with neurological wiring. To have understood this is surely progress. With the externalization apparatus for language in place, the rapid emergence of language itself is far easier to explain. Once this part of the story is complete, we will understand in some detail how the printer for human language works and how it evolved.

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"There is no evidence that great apes, however sophisticated, have any of the crucial distinguishing features of language and ample evidence that they do not.48 Claims made in favor of their semantic powers, we might observe, are wrong. Recent research reveals that the semantic properties of even the simplest words are radically different from anything in animal symbolic systems."

Comment: Before humans developed spoken language there were massive anatomic changes compared to the earliest homos: a dropped pharynx. a protective epiglottis, an arched pallet, special tongue and lip muscles and their brain controls, along with specialized breath controls. All of this appeared before speech. None of this was caused by a need for survival and certainly not driven by environmental demands. In fact none of the development of human characteristics are clearly environmentally driven. Yes, they descended from trees, but that may well have been a voluntary choice to which they then adapted